1. Field of the Invention
The present invention relates generally to the field of revolving windmills, and more particularly to a windmill structure including elongated shaft sections arranged radially about an axial support, and having a pivoting vane on each shaft section spaced about the axial support.
2. Prior Art & General Background
In the past it has been the conventional practice to employ windmills for converting the strength of the wind to useful power or work. Such a conversion is extremely important in modern times, when energy supplies are being recognized as limited, and the non-polluting, almost always available source of power in the wind is an important resource to be developed.
Formerly windmills have performed various useful tasks such as pumping water, generating power and operating machinery and the like. Usually, such windmills utilize the well-known vertical plane, horizontal axis windmill, as disclosed in, for example, U.S. Pat. Nos. 1,256,338 to Liles issued Feb. 12, 1918, and 1,809,919 to Turner issued June 16, 1931, which employ rudder means to maintain the fan or blades of the mill facing into the wind, so as to maximize power output. In many instances, considerable drag is imposed on the fans, louvers or blades of the windmill, as the rotation of the mill causes the blades to meet the oncoming wind stream in a closed position.
To avoid this problem, mechanical devices have been employed for moving the blades or vanes into feathering or operating positions; however such mechanisms themselves are often complex, expensive, unwieldy and inefficient. Such prior attempts at providing automatic feathering using mechanical means are shown and described in U.S. Pat. Nos. 609,378 to Weitzel (issued Aug. 16, 1898), 3,920,354 to Decker (issued Nov. 18, 1975) and 2,006,024 to Lockwood (issued June 15, 1935). The mechanical means for positioning the blades or vanes from operating positions, normally closing air passage ways through the windmill, and in feathering positions, so that the air passageways are open to oncoming air, are slow in response to change of wind conditions and direction, so that the efficiency of the windmill is greatly reduced.
However, a class of windmills exists which does not feature a directional rudder or control mechanism. These windmills are omnidirectional and operate on the principle of rotating in a horizontal orbit as described in, for example, U.S. Pat. No. 1,581,537 to Hennigh issued Apr. 20, 1926, U.S. Pat. No. 1,915,689 to Moore issued June 27, 1933, and U.S. Pat. No. 2,441,635 to Iverson issued May 18, 1948.
With this type of windmill, the vanes are generally spaced about a vertical axial mast at right angles to each other and coupled to each other, flipping up and down as they rotate in their horizontal orbit, and, in general, have stops to limit the motion of the vanes to just a particular 90 degree oscillation.
Also, with this type of windmill and with other types of horizontally rotating windmills, arrangements have been taught for feathering the vanes, and it is well known in the art to have, for example, a rudder movable by the direction of the wind to position components for regulating the speed of the windmill. For example, Kenworthy in U.S. Pat. No. 786,297 issued on Apr. 4, 1905, uses a rudder to position a rail constituting a cam, which engages the lower portion of the blades or vanes for tilting and feathering the blades. The rail is vertically movable by means of a lever fulcrummed upon a carrier having a weight adjustable upon the lever, an arm which rises from the inner portion of the lever and a link pivoted to the upper end of the arm and pivotally connected to a vertically movable sleeve, which carries the rail for movement therewith, so that the blades may be properly feathered as they travel into the wind.
For other examples of windwheels, which use a rudder in combination with other components for regulating the speed of the windmill, see U.S. Pat. Nos. 83,620 to Frazee issued on Nov. 3, 1868, 615,782 to Bartholomew issued on Dec. 13, 1898, and 794,706 to Fine issued on July 18, 1905, and French Patent No. 2,288,878 deposited Oct. 24, 1974. For an example of a neutralizing cylinder having a piston rod adapted to be moved, for example, manually to turn all the blades or vanes to a horizontal position in such a manner to render the device inoperative, see the patent to Iverson. For an example of springs, which are used to prevent possible breaking or warping of the vanes in a high wind and are sufficiently strong to resist ordinary wind pressure for holding the vanes vertical, while yielding under excessive pressure to permit the vertical vanes to flatten out backward or with the wind, see the patent to Moore.
With the windmills such as Iverson, Hennigh and FIG. 5 of Moore, the vanes may have a natural, generally unbalanced configuration. Accordingly, it is known that outboard counterweights, as taught by Moore, may be provided which lie in positions at right angles and parallel to a wind plane respectively, may act to balance the vanes, so that they normally lie in positions at right angles and parallel to a wind plane respectively, so that they are always in a position to take advantage of the slightest breeze and allow the windmill to be capable of operating at a lower threshold of wind speed, for example, 5 m.p.h. than a 10 m.p.h. speed, as may be required by the omnidirectional windmills which are not balanced. This is because additional work has to be done in order to rotate the surfaces around the axis in conjunction with the work done in overcoming the inertia of the surfaces. Accordingly, axial balancing eliminates the additional work caused by the surfaces themselves arranged around the horizontal axis and cancels the effect of non-offset weight.
For other examples of patents for converting wind power into rotary motion, see Italian Patent No. 630,487 published in 1961, French Patent No. 364,033 published in 1906, West German Patent No. 2,644,557 published Apr. 6, 1978, and U.S. Pat. Nos. 2,439,575 to Morris issued Apr. 13, 1948, and 4,186,313 to Wurtz issued Jan. 29, 1980. For an example of a windmill which rotates in a horizontal orbit and features camming by means of a crank and slanting paths to flip the vanes up and down, see U.S. Pat. No. 2,397,346 to Gimenez issued on Mar. 26, 1946. For a further example of a patent which teaches an impulse turbine for converting rotary motion to reciprocating motion see Australian Patent No. 213,550 to Ferguson et al published in 1957.